Spider beetles are common pests found in stored products, but their physical appearance may cause confusion. These insects are two to five mm long, oval or cylindrical, long-legged, and brown in color with a superficial resemblance to spiders, hence their name source.
While many insects have wings, spider beetles possess a unique structure. Their first pair of wings are hardened and thickened, serving as a protective shield for the fragile flying wings tucked underneath source. This Latin name for this order, Coleoptera, translates to “folded wing,” which provides a hint about their ability to fly.
What Are Spider Beetles
Size and Appearance
Spider beetles are small household pests, typically measuring between two to five millimeters in length. They have an oval or cylindrical body and are brown in color. These insects have long legs, giving them a superficial resemblance to spiders, hence their name.
Description
Often infesting stored products, spider beetles are common and widespread across the United States. However, they are not as abundant nor well-known as other household pests such as ants and cockroaches. Their appearance may cause alarm, but they are generally considered a nuisance and not harmful.
Notes
- Spider beetles belong to a group of insects called Coleoptera.
- Several species of spider beetles exist in the U.S.
- They are more commonly found in dark, secluded areas like basements and attics.
In comparison to other common household pests, spider beetles have some key distinctions:
| Feature | Spider Beetle | Cockroach |
|---|---|---|
| Size | 2-5mm | 10-50mm |
| Body Shape | Oval | Flat |
| Color | Brown | Brown |
| Legs | Long | Short |
| Infestation Risk | Low | High |
While spider beetles may be an unwelcome sight, their presence typically does not pose the same level of threat as an infestation of other, more destructive household pests. If encountered, it is important to identify and remove any infested stored products to prevent further infestation.
Physical Attributes and Abilities
Do Spider Beetles Have Wings
Yes, spider beetles have wings, but they are usually hidden and not used for flight. Their wings are primarily for protecting the beetle’s delicate abdomen.
Example:
- Featherwing beetles have wings that are folded out of sight under their body, which helps them float like dandelion seeds in the air 1.
Other Body Features
Spider beetles are known for their unique body features. Some of their prominent characteristics include:
In the development stage, spider beetle larvae have a segmented body with three pairs of legs near the head and a pair of leg-like appendages near the back.
Comparison Table:
| Spider Beetles | Other Beetles |
|---|---|
| Long legs | Shorter legs |
| Oval/cylindrical body | Varied shapes |
| Brown color | Varied colors |
| Mostly 2-5 mm long | Varied sizes |
Now that we understand the physical attributes, spider beetles have unique features such as wings that are not used for flying and long legs that resemble spiders. Keep in mind these features can vary depending on the species.
Behavior and Habitat
Habits and Diet
Spider beetles are not as well-known as other household pests, but they do infest stored products in various households across the U.S 1. They are known to be:
- Oval or cylindrical
- Long-legged
- Brown in color
These tiny insects, which measure between two to five millimeters in length, are often mistaken for spiders because of their superficial resemblance 1. One of their peculiar habits involves playing dead when disturbed, similar to certain spiders. The primary food source for these beetles is typically found in stored products like grains, cereals, or even dead insects.
Preferred Living Conditions
While preferring a habitat with an ample food source, spider beetles can also be found in other areas such as ceilings or any hard-to-reach places. Since they’re so adaptable, they can thrive in numerous environments. However, these beetles don’t spin webs like spiders do2. Their living requirements can be summarized as:
- Access to stored products (food source)
- Concealed or hard-to-reach areas
- Ability to avoid predators by playing dead
| Features | Spiders | Spider Beetles |
|---|---|---|
| Preferred Habitat | Various environments | Stored products, concealed spaces |
| Webs | Yes | No |
| Playing Dead | Some species | Yes |
| Legs | 8 | 6 |
Life Cycle and Development
From Larvae to Adult
Spider beetles undergo a complete metamorphosis, consisting of four life stages: egg, larva, pupa, and adult. The larvae hatch from eggs and feed on various organic materials, eventually spinning cocoons to transform into pupae. Within these cocoons, they undergo the transition to adulthood.
Adult spider beetles have wings but are generally poor fliers. Their life cycle can take anywhere from a few months to over a year, depending on environmental conditions and food availability.
Signs of Spider Beetle Infestation
- Presence of tiny, round fecal pellets
- Damaged stored goods (grains, cereals, pet food)
- Sightings of live or dead beetles
- Shed skins or cocoons from the pupal stage
Comparison Table
| Spider Beetle | Other Common Beetles |
|---|---|
| Poor fliers | Can fly long distances |
| Infest stored goods | Typically feed on plants or wood |
| Small and reddish-brown | Vary in size and color |
| Complete metamorphosis | Varies by species |
Identifying Spider Beetles
Visual Clues
Spider beetles are small insects, usually two to five mm long, oval or cylindrical, with long legs and generally brown in color. Their appearance can be confusing, as some species resemble spiders, hence their common name.
Preventing Mistaken Identity
To correctly identify spider beetles, it’s important to know some of their distinguishing features:
- Long legs: Longer than other beetles, giving them a “spider-like” appearance.
- Size: They are generally smaller than most other beetles, ranging from 2-5mm in length.
- Color: Mostly brown, but some species may display variations in color.
Compare spider beetles to some other common insects like ladybugs or milkweed bugs that have their unique features:
| Insect | Size | Color | Shape |
|---|---|---|---|
| Ladybugs | 1/4 – 3/8″ long | Black to pink, yellow, or red | Round or oval and convex |
| Milkweed Bugs | Large – ¾” long | Orange to reddish-orange | Elongated and oval |
| Spider Beetles | 2-5mm long | Brown | Oval or cylindrical |
Remember to consider these visual clues and comparisons when identifying spider beetles to avoid misconceptions with other insects.
Footnotes
6 Comments. Leave new
Do they crawl slowly then do these Beatles have wings and fly.
We do not believe Spider Beetles are capable of flight.
i recently came across this in my brooklyn NY apt….this was in my bathtub, very tiny, .. but mine are slow, (maybe because the tub was cold ?).. i see them only once and awhile.
they are very tiny, …. i dont see pinchers, like the pseudoscorpion, ..
I just found one in the bathroom, of the hotel we are staying at!
I probably have spider beetles. They are the dice of a tick or smaller. Do not move for days at a time. Looks like a bit of dirt but smear when they are crushed. They are in my powder room and along the crevice where carpet meets the woodwork under my living room windows. I also see some in the master bath on the floor. I am in a townhouse on a slab send I have two cats.
What are they and how do I get rid of them?